# Thread: calculating front seat height

1. ## calculating front seat height

What is the correct way to calculate the front seat height (FSH)? This is also known as the front seat to floor measurement. I'm guessing the way to do it is to take your heel to knee measurement and apply this formula.

(heel to knee) - (cushion height) + (footrest height) = FSH

Footrest height is the distance between the floor and the top of the footrest.

And by heel to knee, I'm referring the distance between the bottom of your heel to the part of the lower leg just below the knee (parallel to the top of the seat cushion).

2. just measure from the floor to the front edge of your seat pan without the cushion. thats your front seat to floor height. same thing for rear seat to floor.

3. I'm not asking how to measure an old chair. I'm trying to firgure out what front seat height I should get on a new chair.

My old chair's FSH isn't working for me, so I need to know how to calculate it based on my body size.

4. Originally Posted by Justin S
I'm not asking how to measure an old chair. I'm trying to firgure out what front seat height I should get on a new chair.

My old chair's FSH isn't working for me, so I need to know how to calculate it based on my body size.
What's wrong with the seat height on your old chair? Too high? Too low? Use that as a starting point and go from there.

C.

5. And get the angle meter out to check your shin bone in an 'as used' state and learn geometry as well. The old chair is a good basis, but also remember angles and how you foot will actually be on the foot rest as well. Consider shoes in the equation also.

If one would measure front height on my chair without considering angle and foot position, it would be about 2 or 3 inches too short if my legs were 'as expected' to be on the footplate. BUT, as the balls of my feet are actually on the footplate causing my heel to dip down behind the plate, that shaves some leg length and maybe prevents that 'foot drop' from happening as well. Also, my knee's front most part is also at my big toe's most forward position as well, so my leg is actually bent beyond 90 degrees, creating more space as well. Much more going on than the 85 degree angle of the front of my chair would suggest. Also, try to set something up with a reversed footplate so that it is the furthest forward part of the chair with you in it. Great for pushing objects and opening doors with no injury to yourself in the process.

6. Originally Posted by Tiger Racing
What's wrong with the seat height on your old chair? Too high? Too low? Use that as a starting point and go from there.

C.
My knees are too high and this prevents me from fitting under desks and whatnot. My old chair has a 19.5 inch seat height. I want to reduce it by 1 inch, but I'm just trying to make sure this won't have any unforseen consequences.

7. like your footplates dragging everywhere ya go outside. I RARELY find a table I can get under.
can you get smaller front casters and raise the rear by as much to retain dump....etc
Like Andy said, I think he has 90 deg footplate angle(part of chair frame) and heels drop lower than toes, ya pick up an inch or two
My chair has legrests that are removable and stick out a yard in front of me because I have looong legs.
I'd use my present chair measurement as a starting point and see what caster size change would bring to the equation.
You are in Austin, don't the have dealers you can go test chairs at there? If so, that would be my FIRST choice and take a tape measure.

8. If you are still thinking ergo seat, make sure you will still have the amount of seat dump you are comfortable with. Also note that for the ZR/ZRa, the front STF height is the highest point of the tubing--not the upholstery. Another option to get your knees lower would be to order a 19" front STF and get TiLite's Designs Unlimited special to build it with a deeper cross tube (DU10005). That would allow you to sag your upholstery to sit a little lower without bottoming on the cross tube if you needed to.

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